The present invention relates to quick setting polymer concrete compositions which will set to polymer concretes having high compressive strength. Some embodiments achieve compressive strengths in excess of 2000 psi within one hour after mixing. The polymer concrete compositions comprise unsaturated polyester compositions including a crosslinking monomer and a minor proportion of at least one promoter and initiator together with a source of bivalent metallic ions. The latter may be contained in an aggregate system or independent thereof.
A need exists for compositions suitable for the rapid repair of deteriorated portland cement concrete bridge decks and highways and for construction material for pipes, slabs, wall panels and the like. The need is particularly acute for compositions that can be used for the simple and rapid reapir, under all weather conditions, of damaged aircraft runways.
Materials currently receiving world wide attention for these needs are known as polymer concretes (PC) and generally comprise an aggregate system and a polymeric binder. To produce PC, the aggregate is normally mixed with a monomer or curable polymer formulation and subsequently cured in place.
PC can be made using a variety of polymeric materials such as epoxies, polyester, methyl metacrylate (MMA) and mixtures of MMA with other acrylics as crosslinking agents.
Aircraft runway repair, particularly under combat situations, imposes many criteria not normally met in the repair of ordinary commercial facilities. The repair must be simple, rapid and produce a patch capable of standing up under stress of use by heavy, high speed aircraft. The repair systems must be capable of use under all weather conditions including a wide range of temperatures, e.g. -5.degree. C. to 40.degree. C. and all forms of precipitation. Specifically, the rapid curing compositions should be compatible with water, curable in less than an hour over a temperature range from -5.degree. C. to 40.degree. C. to a product with compressive strength of more than 2000 psi, a flexural strength greater than 500 psi, and a bond strength greater than 200 psi. Additionally, the system should be low cost, stable over long periods of time under all weather conditions, nontoxic, and nonflammable or at least flame resistant.
Ester types of unsaturated polyester concrete (UP-PC) comprising UP-styrene compositions and dry aggregate are currently being widely employed as rapid repair materials for portland cement concrete (PCC) structures. These materials cannot be used under conditions of high humidity or with wet aggregate because rapid hydrolysis of the ester groups leads to the production of PC patches with very low strengths. For example, the compressive strength of UP-PC containing wet aggregate (8% water content) was found to be zero at the end of one hour and only 830 psi at the end of 24 hours.